Apparatus and method for conserving and restoring oil paintings and the like



July 2, 1963 G. D. KLIMANN 3,

APPARATUS AND METHOD FOR CONSERVING AND RESTORING OIL PAINTINGS AND THE LIKE Filed June 30, 1960 INVENTOR.

GUSTAV D. KLIMANN BY raw, W M

ATTOR N EYS United States Patent Ofifice 3,-95,l94 Patented July 2, 1963 APPARATUS AND METlifil) FOR CONSERVHNG AND RESTOG 91L PAINTINGS AND THE LEKE Gustav D. Klimann, l Weilesley Road, Beverly, Mass. Filed June 30, 1960, Ser. No. 40,092 Claims. (Cl. 1l72) This invention relates to an apparatus for and a method of conserving and restoring oil paintings and the like; and more particularly to an apparatus and method for impregnating an oil painting or the like with varying amounts and kinds of suitable resins and waxes, and for incorporating thereto, when desired, new backings of appropriate supporting materials, such as canvas, while, and by, subjecting the painting to the influence of heat and substantial vacuum.

The chemical make-up of paintings, and indeed of the the materials used in artistic canvas to which the materials are applied, is such that in time they become dr brittle, and dirt-laden and begin to chip and flake. In the past, inexpert attempts to conserve, clean and restore paintings in such a condition have often done more harm than good. irreparable damage has been done to some of the worlds great masterpieces through the abrasive and distorting action of mechanical cleaning devices and through the chemical action of cleaning agents ill-suited to the task of removing dirt from painted surfaces. Furthermore, even mechanically non-abrasive and chemically mild cleaning materials and methods often failed in their purposes because the insides and backings of the paintings under treatment, which were often in as dirty and decomposed a condition as the painted surfaces themselves, were left untouched.

Improvements involving impregnation of the painting with various cleaning and strengthening materials for both the painted surface and the backing also left much to be desired, because the pressure necessary to cause impregnation was applied by means of a screw press or an iron. Owing to surface irregularities of the iron or press and of the painting and owing to the relatively small area of the iron or press, in many cases, as compared to the area of the painting, such means of applying pressure were likely to cause too great pressure on one part of the surfaceeven to the point of crushing it-and little or none on another part. In addition, such pressing and ironing methods were relatively slow and expensive.

It is an object of my invention to remedy the situation described above by providing for uniform pressure on and hence uniform impregnation of the painting under treatment. it is a further object of my invention to facilitate the impregnation by means of heat and vacuum. It is a further object of my invention to provide an inexpensive airtight means which is sufliciently voluminous to prevent rapid loss of vacuum in the event of small leaks and yet strong enough to withstand the evacuation of the air within the enclosed space. It is a further object of my invention to provide means whereby a plurality of paintings can be treated simultaneously without increasing the risk of damage to any one.

In the accomplishment of these and other objects of my invention I employ a heating table with, in one embodiment, a Masonite top inlaid with Nichrome wire filament, and, in another embodiment, a top consisting of a shallow water-carrying tank, suitably bafiled, and with an inlet and an outlet for the introduction and removal of hot or cold water. In both embodiments, I place an airtight rubber sandwich on said heating table, consisting of two sheets of pure gum rubber joined together at and near their periphery and enclosing sheets of wax paper, resin-impregnated paper, Masonite boards for stiffness and smoothness, and elongated vacuum preservers to prevent the complete collapse of said rubber sandwich when the air is evacuated therefrom. At a suitable place within said sandwich I insert the painting to be cleaned, conserved, or restored. I then evacuate the air within the sandwich and apply sufiicient heat to cause impregnation of the painting by the wax and resin.

It is a feature of my invention that a plurality of paintings can be treated in a single operation without increasing the risk of damage to any one painting. It is a further feature of my invention that the wax and resin will uniformly impregnate the painting even at relatively low temperature because of the low pressure within the sandwich and correspondingly high volatility of the impregnating materials. It is a further feature of my invention that the elongated vacuum preservers will prevent sudden loss of air pressure in the event of minute air leaks. It is a further feature that the vacuum preservers, which are placed upon a Masonite foundation, will distribute the air pressure evenly over the surface of the picture, leaving no ridges or marks thereon. It is a still further feature of my invention that the picture can be quickly cooled in the embodiment wherein a tank is employed as the heat ing element, simply by flushing cold water therethrough. Thus, I have provided an apparatus for and a method of conserving and restoring oil paintings and the like which permit maximum cleaning, conserving, and restoration at a minimum risk of harm due to accident, uneven pressure,

etc.

These and other objects and features of my invention will best be understood and appreciated from the following description of two preferred embodiments thereof, selected for purposes of illustration, and shown in the accompanying drawings, in which:

FIG. 1 is a perspective view of the first embodiment as it appears in actual use, showing a rubber sandwich 8 (with a valve 14} for exhausting the air therefrom) resting on a heating table 12;

FIG. 2 is an exploded perspective view of the first embodiment; and

FIG. 3 is a plan view of the heating element employed in a second preferred embodiment.

In the first preferred embodiment of my invention I employ a heating table 12 with a Masonite top 14 inlaid with Nichrome wire filaments 16 set in A5 grooves 18, said filaments 16 extending in coiled fashion or otherwise substantially uniformly over a rectangular area approximately 60 by 40", and developing total power of about LOGO watts when the lead ends 20 are connected to ordinary house current. Said filaments 16 can consist a plurality of separate circuits, conveniently four, each developing about 250 watts.

Centered in horizontal sandwiched relation immediately above said heating table 12 1 construct a rubber sandwich 8 as follows: First I lay a sheet of pure gum rubber 22, measuring A; by 60" by 48". Centered in horizontal sandwiched relation immediately above said rubber sheet are the following elements, from bottom to top, all measuring 52" by 42": a sheet of Masonite 24, having a thickness of A and laid smooth side up; a sheet of semi-absorbent paper, such as kraft brown paper 26; a sheet of glazed insulation paper 28, glassine type; and a sheet of wax impregnated paper, such as butchers paper 3! (Centered in horizontal sandwiched relation immediately above said butchers paper 30 I place the paintings 32 and 32a to be cleaned or restored, face up, without overlapping one another, and within a rectangle centered upon said butchers paper 30 and measuring 50" by 40". The faces of said paintings 32 and 32a are covered with wet-strength paper 34 in order to strengthen and protect said faces during treatment, and the reverse sides are covered with fresh linen 36 to be bonded to the old and deteriorated canvas.) Continuing the construcaoaenee tion of the rubber sandwich 8, l next center in horizontal sandwiched relation immediately above said Wetstrength paper the following elements, from bottom to top, all measuring 52" by 42": a sheet of butchers paper 38; a sheet of glazed insulation paper 40, glassine type; a sheet of kraft brown paper 42; and a sheet of Masonite 44, A" thick, smooth side down. Above said Masonite 44 I arrange elongated vacuum preservers 46 and 46a extending in several directions at spaced intervals, such as sticks or rods or wood or metal in the shape of rectangular parallelepipeds and arranged in network or honeycombed fashion. Above said vacuum preservers 46 and tea I place weights 48 at suitable intervals to provide additional means for urging said resinous and wax substances 28, 30, 3S, and 49 into close proximity to said paintings 32 and 32a. I place a flexible protector 50, consisting of a heavy sheet of rubber or similar material. To complete the rubber sandwich 8 I place another sheet of pure gum rubber 52, measuring 60" by 40", in horizontal sandwiched relation above said protector t containing an exhaust valve it to which a vacuum pump may be attached, and in physical contact at and near its periphery 52a with the corresponding part 22a of the rubber sheet 22. Said sheets are held together during treatment of the paintings by the weight of the upper sheet and air pressure along, but additional weights 54 may be placed along the periphery of the sandwich to facilitate the forming of an airtight seal while the vacuum is being established.

The fresh linen 35 may, of course, be omitted, if it is not desired to add new backing to the painting.

In cleaning and restoring a painting, a rubber sandwich is first constructed (and the painting inserted therein) as described above and placed upon the heating table 12 as shown in FIG. 1. In the second preferred embodiment the sandwich is placed instead on the heating table 56. In either case the air is then evacuated from the space enclosed by the sandwich 8 through the valve 10. The vacuum preservers 46 and 46a prevent the complete collapse of the sandwich 8 and ensure a relatively large space from which the air is evacuated, so that in the event of minute air leaks the vacuum may neverthless last for several hours. Heat is then applied (by the filaments 16 in the first embodiment and by the Water tank 56 in the second), causing melting and/or volatilization of the waxes and/or resins 2%, 39, 38, and 40 and resulting in impregnation under low atmospheric pressure of the paintings 32 and 32a. In the usual case, the temperature is maintained at about 200 degrees Fahrenheit for about an hour. The paintings 32 and 32a are allowed to cool for several hours (or, in the second embodiment, are cooled rapidly by flushing cold water among the baflies 58 of t e tank 56) whereupon they are removed from the sandwic The wet-strength paper 34 is peeled from the painted surfaces, which may then be coated in the usual manner with suitable plastic or varnish in order to preserve them.

By employing vacuum in this manner it will be seen that the air spaces or interstices in the canvas backing of the painting, as well as the microscopic air spaces in the painting surface itself are evacuated and thereby permit a free and unobstmcted access for the Waxes and/or resin employed in the restoration process. Also it will be understood that the vacuum acts predominantly uniformly across the face of the sandwich despite the fact that the elongated vacuum preserves 46 and 46a and the weights 4:8 are placed above the painting. To be sure these elements cause a slight increase of pressure along the line of their contact, but since the force vector of the vacuum exerted horizontally against these bars does not increase the pressure against the canvas, the added force along the lines of contact is not particularly great. Moreover the Masonite element 44 serves substantially to eliminate all adverse aifects of increased pressure along the lines of contact. In this way I enjoy the benefits of extra Above said weights 48' reserve vacuum created by these elements Without suffering the disadvantages of extreme unevenness in pressure across the face of the painting to be restored.

Certain minor variations of these preferred embodiments will be apparent to those skilled in the art. For instance, the heating means could be other than those described. Specifically, hot-Water pipes could be employed. Alternate means could be used to seal the periphery 24a of the rubber sheet 24 to the periphery 52a of the rubber sheet 52. The /8" grooves 18 could be of different sizes. Additional Masonite, or a conductor in place of the Masonite such as aluminum, could be used. Higher or lower temperatures or sandwich sheets of materials of differing thermal conductivity could be used for different lengths of desired treatment time. Therefore, it is not my purpose to confine the invention to the precise form herein shown but rather to limit it in terms of the appended claims.

Having thus described and disclosed ,two preferred.

embodiments of my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A- method of conserving, restoring and facilitating the cleaning of oil paintings and the like comprising the steps of; placing a sheet of wet-strength paper over the painted surface; superimposing successively both above and below the painting, a sheet of wax impregnated paper, a sheet of insulation paper, a sheet of semi-absorbent paper and a substantially rigid panel; placing the materials thus sandwiched together Within a substantially airtight, collapsible container; evacuating the air from within said container; raising the temperature within said container and subsequently permitting said container to cool; releasing the vacuum created in said container; opening said container and disassembling the said sandwiched materials and removing the painting and stripping the wetstrength paper therefrom.

2. A method of conserving, restoring and facilitating the cleaning of oil paintings and the like as set forth in claim 1 in which the temperature within said container is raised to approximately 200 F. and is maintained for one hour.

3. A method of conserving, restoring and facilitating the cleaning of oil paintings and the like as set forth in claim 1 in which substantially all of the air within said container is evacuated to cause said container to collapse upon said sandwiched materials and to exert a pressure thereon approximating atmospheric pressure.

4. A method of conserving, restoring and facilitating the cleaning of oil paintings and the like as set forth in claim 1 in which said sheet of wax impregnated paper comprises a sheet of butchers wax paper.

5. A method of conserving, restoring and facilitating the cleaning of oil paintings and the like as set forth in claim 1 in which said sheet of semi-absorbent paper comprises a sheet of kraft brown paper. 7

6. An apparatus for conserving, restoring, and facilitating the cleaning of oil paintings and the like comprising a flexible envelope for completely enclosing one or more paintings; means for substantially evacuating the air from within said envelope .to cause said envelope to collapse; means positioned within the said envelope to prevent it from collapsing entirely whereby a partial vacuum may be created wtihin the said envelope, said last mentioned means including at least a rigid panel positioned on each side of said painting etween the said painting and the said envelope; means for heating said collapsed container; means within said envelope for releasing a bonding substance upon the application of heat and in the presence of a partial vacuum, said last mentioned means comprising a sheet of butchers Wax paper positioned at each side of said painting between said painting and said rigid panels; and insulation means including a sheet of glassine insulation paper and a sheet of semi-absorbent paper positioned at each side of said painting between said ibutchers wax paper and said rigid panels.

7. An apparatus as defined in claim 6 wherein said collapsible envelope comprises a first and a second sheet of pure gum rubber and wherein said envelope is caused to be airtight by the action of atmospheric pressure upon the pheriphery of the said first and said second sheets.

8. Apparatus for conserving, restoring, and facilitating the cleaning of oil paintings and the like comprising a base; a flexible container positioned upon said base, said flexible container comprising a first and a second sheet of pure gum rubber each said sheet being substantially coextensive with said base, said first sheet being positioned upon and overlying said second sheet; means for substantially evacuating the air from between said first sheet and said second sheet; means for retaining said first sheet and said second sheet in a spaced apart condition despite the evacuation of air therefrom comprising a rigid panel positioned at each side of the painting to be cleaned and additional members positioned between the said rigid panels and said first sheet and said second sheet respectively whereby said first sheet and said second sheet cannot collapse entirely upon said rigid panels; means for releasing suitable bonding and impregnating substances upon the application of heat in the presence of a partial vacuum positioned within said container between said painting and said rigid panels, said last mentioned means comprising a sheet of butchers Wax paper; means for insulating said rigid panels and said first sheet and said second sheet from said bonding and impregnating substances comprising a sheet of glassine insulation paper and a sheet of kraft brown paper positioned at each side of said painting between said butchers wax paper and said rigid panels, and heating means disposed in said base for heating said container and its contents.

9. Apparatus as defined in claim 8 wherein said heating means comprise a series of grooves in said base having a Nichrome wire filament laid therein and said filament being connected to an external supply of electricity.

10. Apparatus as defined in claim 8 in which said heating means comprise a series of heating pipes disposed in said base and means for passing a heated fluid through said pipes.

References Cited in the file of this patent UNITED STATES PATENTS 1,928,105 Kern Sept. 26, 1933 2,073,802 Oliver Mar. 16, 1937 2,872,344 Mees Feb. 3, 1959 FOREIGN PATENTS 488,315 Great Britain July 5, 1938 

1. A METHOD OF CONSERVING, RESTORING AND FACILITATING THE CLEANING OF OIL PAINTINGS AND THE LIKE COMPRISING THE STEPS OF; PLACING A SHEET OF WET-STRENGTH PAPER OVER THE PAINTED SURFACE; SUPERIMPOSING SUCCESSIVELY BOTH ABOVE AND BELOW THE PAINTING, A SHEET OF WAX IMPREGNATED PAPER, A SHEET OF INSULATION PAPER, A SHEET OF SEMI-ABSORBENT PAPER AND A SUBSTANTIALLY RIGID PANEL; PLACING THE MATERIALS THUS SANDWICHED TOGETHER WITHIN A SUBSTANTIALY AIRTIGHT, COLLAPSIBLE CONTAINER; EVACUATING THE AIR FROM WITHIN SAID CONTAINER; RISING THE TEMPERATURE WITHIN SAID CONTAINER AND SUBSEQUENTLY PERMITTING SAID CONTAINER TO COOL; RELEASING THE VACUUM CREATED IN SAID CONTAINER; OPENING SAID CONTAINER AND DISASSEMBLING THE SAID SANDWICHED MATERIALS AND REMOVING THE PAINTING AND STRIPPING THE WETSTRENGTH PAPER THEREFROM. 